Phonograph-reproducer.



N0. 690,069. Patented Dec. 3|, I90I.

- E. H. MOBLEY.

PHONOGRA'PH BEPRO'DUGEB.

(Application filed July 8, 1901.) (No Model.)

m: mums PETERS w PHOYQ-IJYHON WASHINGTON. 11 c NITED STATES PATENT OFFICE.

EDWIN II. MOBLEY, OF PHILADELPHIA, PENNSYLVANIA.

PHONOGRAPH-REPRODUCER.

SPECIFICATION forming part of Letters Patent N 0. 690,069, dated December 31, 1901.

Application filed July 3,1901. Serial No. 66,942. (No model.)

. phonograph-rcproducers as now constructed are to a large extent due to the fact that the stylus or reproducer point is not held with sufficient pressure upon the surface of the cylinder to accurately follow the grooves therein. It is usual to employ a plate hinged at one side to the ring of the reproducer and carrying the fulcrum of the stylus-operating lever; but heretofore it has not been practical to impart sufficient weight to this pressureplate without unduly increasing its thickness and the distance between the diaphragm and the surface of the cylinder.

It is one of the objects of my invention to overcome this difficulty by increasing the downward pressure of the stylus without necessarily increasing, but even when desired decreasing, the thickness of the plate between the diaphragm and cylinder, so that a maximum tension may be obtained with a minimum thickness of plate and without interfering with the freedom of movement of the stylus in following the irregularities of the grooved surface of the record-cylinder. This object I accomplish by providing the plate which carries the stylus-lever with a leverage extension projecting laterally beyond the reproducer-ring. This may be made either in a single unitary piece with the plate or as a separate piece adapted to be attached to the plate as now commonly employed. This leverage extension may be made of any length and thickness to suit the requirements.

In the drawings, Figure 1 is a transverse sectional view of a phonograph reproducer embodying my improvements. Fig. 2 is a similar view illustratinga modification. Fig. 3 is an inverted plan view of the reproducer. Figs. at and 5 are respectively perspective and inverted perspective views of the controllingweight of the form shown in Fig.2, and Fig. 6 is a transverse sectional view of the diaphragm.

Ct is the diaphragm, to which is secured the shank I), connected by the link 0 with the stylus-lever d, which is pivoted to a lug or post 6, carried by the hinged controlling-weighty. The weightf is hinged at one side to the ring 9, and the free end is supported loosely by a pin it engaging a slot or notch. This construction is well known and commonly used; but as at present constructed the controllingweightf to impart the desired pressure to the stylus must be made of considerable thickness.

To enable a greater pressure to be obtained without the necessity of unduly increasing the thickness of the eontrolling-weight,I form the weight with a lateral extension f beyond the fulcrum-post e, which not only enables more weight to be employed,but increases the leverage through which the weight acts, so that an effective downward pressure is obtained without unduly increasing the thickness of the body of the weight adjacent to the stylus. The downward movement of the weightf is usually controlled and limited by a screw or pin h on the ring g engaging a notch or aperture] in the Weight, and the extension f is preferably formed beyond this point extending outwardly and curving over the record-cylinder. This extension may be thickened or weighted at its extremity to any extent desired to increase the weight and downward pressure. The weight with this leverage extension is preferably constructed in a single unitary piece,as shown in Figs. 2, 4, and5; but in some cases Where the reproducer is already provided with the ordinary weight, such as is now used, the leverage-extension weight may be made as a separate piece f and applied to the ordinary weight, as shown in Fig. 1.

7r; is the tube of the reproducer through which the vibrations are transmitted. Instead of forming the mouth of the tube with flat walls, as is customary, I arch them so as to form a dome-shaped mouth m, as shown, Which not only increases the air-space behind the diaphragm, but materially aids in the transmission of the sound-waves.

Owing to the liability of the post I) becoming loosened or detached from the diaphragm a if cemented thereto, as is customary, I prefer to rivet it to the diaphragm, as shown in Fig. 6. The diaphragm is clamped between washers 0 0, in which the post I) is riveted.

What I claim as new, and desire to secure by Letters Patent, is as follows:

1. In a phonograph-reproducer, the combination with the reproducer-head and the stylus-operatin g lever, of a hinged plate or frame carrying said stylus-operating lever, and provided with a leverage extension f projecting laterally beyond the reproducer-head.

2. In a phonograph-reproducer, the combination with the reproducer-head and the stylus-operatin g lever, of a hinged plate or frame carrying said stylus-operatin g lever, and provided with a leverage extension f projecting laterally beyond the reproducerhead and having a thickened or Weighted extremity.

3. Ina phonograph-reproducer, the combination with the reproducer-head and the stylus-operating lever, of ahinged plate or frame carrying said stylus-operating lever, and provided with a curved leverage extension f projecting laterally beyond the reproducerhead.

4. The stylus-controlling weight for phono-- graph-reproducers consisting of a plate adapted to carry the stylus-operating lever and provided with a leverage extension f, substantially as described.

5. The stylus-controllingweight for phonograph-reproducers consisting of a plate adapted to carry the stylus-operating lever and provided with a curved leverage extension f substantially as described.

6. The stylus-controlling Weight for phonograph-reproducers consisting of a plate adapted to carry the styl us-operating lever and provided with a curved leverage extension f, having a thickened or weighted extremity, substantially as described.

In testimony of which invention I have hereunto set my hand.

EDWIN H. MOBLEY.

Witnesses:

THos. MARTIN SMITH, R. H. KELLY. 

